assuming it is heat related, and it does sound llike that, then the thermal compound or thermal pads that they use can break down with age, and add to that the fact these machines are mass produced and the occasional one will slip through with less then adequate compound then it doesn't really matter how well ventilated the console is unfortunatly. the number of pc's ive came across with overheating problems which were solved simply by replacing the thermal compound is just unbelievable. sending it to sony will do the job but you will pay a hefty amount for the priviledge, whereas if you can find a local computer shop they may be able/willing to do it for far less assuming damage has not been done already. i really can't reccomend either way as sony will definetly fix it for a price but a local shop may be able to fix it for less but also might not. the choice is of course yours so good luck with it.